Disc Rotor Machining – Slotted & Cross Drilled Rotors

The introduction of slotted and cross drilled rotors has left technicians asking the question “Can they be machined?” The answer is “Yes – but there are some important things to remember”.

When machining any disc rotor it is important to make sure that all the mounting faces are clean and undamaged on both the rotors and the tooling. Always make sure that the tool tips are sharp and setup directly opposed to each other.
When machining slotted or cross drilled rotors it is extremely important to remember to always use the slowest feed rate and take the smallest cut.

DO NOT take 1 cut to clean up the disc and then a fine finishing cut as you will damage both the disc rotor and your tool tips. If you need to take 5 or so fine cut passes to clean up the face of the disc then that is ok.

Once you have finished machining the disc rotor, very lightly use 240 grit emery paper to smooth off the fine grooves on the face of the disc rotor. Clean the friction faces with a suitable cleaner like liquid acetone or brake clean. Never use petroleum or silicon based cleaners as they will leave a residue on the disc rotor that will impede brake performance.

Remember Always check rotor thickness & replace if on or under minimum thickness after machining.